Hydroxy-functional fluoropolymers useful in coating compositions are known in the art. For example, U.S. Pat. No. 4,345,057, assigned to Asahi Glass Company, details the synthesis of fluorinated ethylene-(hydroxy-alkyl) vinyl ether (FEVE) copolymers and their application in thermoset coating compositions. Such coatings are useful in forming high gloss, durable topcoats for building panels, automotive body panels and automotive body parts.
Notwithstanding their excellent properties, the use of hydroxy-functional vinyl ethers as the source of the reactable hydroxyl group in these fluoropolymers provides a coating polymer that is relatively expensive. While the good durability of these FEVE coatings is well-known in the coatings industry, there is a need for a more cost-effective fluoropolymer that can provide similar properties.
Co-pending and commonly-owned U.S. patent application Ser. No. 08/541,748, now U.S. Pat. No. 5,750,770, and commonly-owned U.S. Pat. No. 5,612,416 both disclose the synthesis and use in coating compositions of copolymers which comprise alternating units of a vinyl monomer and a diester of an unsaturated anhydride in which at least one of the esterifying groups includes a hydroxyl group. The commonly-owned application and patent also disclose the synthesis and use in coating compositions of terpolymers which comprise alternating units of hydroxyalkyl maleates, vinyl monomers and fluoromonomers.